As this type of damper mechanism or a high pressure fuel pump provided with the damper mechanism, various dumpers and pumps have been conventionally known. One example is a single metal diaphragm damper and a high pressure fuel pump provided with the single metal diaphragm damper. The single metal diaphragm damper is so constituted that the peripheral portion of a single metal diaphragm is secured in a housing by welding. (Refer to Japanese Patent Laid-Open No. 2000-193186 and Japanese Patent Publication No. 3180948.)